–

–

–

–

12

13

NMEA Output Messages

The following sections outline the data structures of the various NMEA

messages that are supported by the module. By default, the commands

are at 9,600bps, 8 data bits, 1 start bit, 2 stop bits, and no parity.

GGA – Global Positioning System Fixed Data

Figure 8 contains the values for the following example:

$GPGGA,053740.000,2503.6319,N,12136.0099,E,1,08,1.1,63.8,M,15.2,M,,0000*64

Global Positioning System Fixed Data Example

Name

Example

Units

Description

Message ID

$GPGGA

GGA protocol header

UTC Time

053740.000

hhmmss.sss

Latitude

2503.6319

ddmm.mmmm

N/S Indicator

N

N=north or S=south

Longitude

12136.0099

dddmm.mmmm

E/W Indicator

E

E=east or W=west

Position Fix Indicator

1

See Figure 9

Satellites Used

08

Range 0 to 12.

HDOP

1.1

Horizontal Dilution of Precision

MSL Altitude

63.8

meters

Units

M

meters

Geoid Separation

15.2

meters

Units

M

meters

Age of Diff. Corr.

second

Null fields when DGPS is not used

Diff. Ref. Station

0000

Checksum

*64

<CR> <LF>

End of message termination

Figure 8: Global Positioning System Fixed Data Example

Position Indicator Values

Value

Description

0

Fix not available or invalid

1

GPS SPS Mode, fix valid

2

Differential GPS, SPS Mode, fix valid

3–5

Not supported

6

Dead Reckoning Mode, fix valid

Figure 9: Position Indicator Values

GLL – Geographic Position – Latitude / Longitude

Figure 10 contains the values for the following example:

$GPGLL,2503.6319,N,12136.0099,E,053740.000,A,A*52

GSA – GPS DOP and Active Satellites

Figure 11 contains the values for the following example:

$GPGSA,A,3,24,07,17,11,28,08,20,04,,,,,2.0,1.1,1.7*35

GPS DOP and Active Satellites Example

Name

Example

Units

Description

Message ID

$GPGSA

GSA protocol header

Mode 1

A

See Figure 12

Mode 2

3

1=No fix, 2=2D, 3=3D

ID of satellite used

24

Sv on Channel 1

ID of satellite used

07

Sv on Channel 2

...

...

ID of satellite used

Sv on Channel 12

PDOP

2.0

Position Dilution of Precision

HDOP

1.1

Horizontal Dilution of Precision

VDOP

1.7

Vertical Dilution of Precision

Checksum

*35

<CR> <LF>

End of message termination

Figure 10: Geographic Position – Latitude / Longitude Example

Geographic Position – Latitude / Longitude Example

Name

Example

Units

Description

Message ID

$GPGLL

GLL protocol header

Latitude

2503.6319

ddmm.mmmm

N/S Indicator

N

N=north or S=south

Longitude

12136.0099

dddmm.mmmm

E/W Indicator

E

E=east or W=west

UTC Time

053740.000

hhmmss.sss

Status

A

A=data valid or V=data not valid

Mode

A

A=autonomous, D=DGPS, N=Data

not valid

Checksum

*52

<CR> <LF>

End of message termination

Figure 11: GPS DOP and Active Satellites Example